1. Field of the Invention
The present invention relates to preceding vehicle following control apparatus and method for an automotive vehicle which perform a vehicular run control to follow a preceding vehicle which is running ahead of the vehicle maintaining an inter-vehicle distance from the vehicle to the preceding vehicle at a target inter-vehicle distance.
2. Description of the Related Art
A Japanese Patent Application First Publication No. Heisei 6-320983 published on Nov. 22, 1994 exemplifies a previously proposed preceding vehicle following control apparatus for an automotive vehicle.
In the above-described previously proposed preceding vehicle following control apparatus, when the preceding vehicle has disappeared from a detection zone of an inter-vehicle distance sensor which is installed on the vehicle while the vehicle follows a preceding vehicle, an acceleration/deceleration target value which is immediately before the preceding vehicle has disappeared therefrom is held for a predetermined time duration. Hence, in a case where the preceding vehicle cannot be detected by means of the inter-vehicle distance sensor during a deceleration of the preceding vehicle due to some cause, the vehicle is decelerated for the predetermined time duration approximately at the same deceleration as the preceding vehicle.
The above-described previously proposed preceding vehicle following control apparatus holds the acceleration/deceleration target value immediately before the preceding vehicle has disappeared from the detection zone of the inter-vehicle distance sensor during the preceding vehicle following of the vehicle when the preceding vehicle has disappeared therefrom. However, there is often a case where the vehicle is gradually accelerated when the preceding vehicle has disappeared therefrom. Especially, since the inter-vehicle distance to the preceding vehicle is short while the vehicle is running at a relatively low vehicular velocity, there are many cases to give a mismatch to a vehicular driver""s sense of vehicular driving.
It is, therefore, an object of the present invention to provide preceding vehicle following control apparatus and method for the automotive vehicle which make the vehicle stop without giving the mismatch to the vehicular driver""s sense of vehicular driving when the vehicle is running in the preceding vehicle following control at a low vehicular velocity region and the preceding vehicle has not been detected by an inter-vehicle distance detector.
According to one aspect of the present invention, there is provided a preceding vehicle following control apparatus for an automotive vehicle, comprising: a vehicular velocity detector to detect a vehicular velocity of the vehicle; an inter-vehicle distance detector to trap a presence of a preceding vehicle which is running ahead of the vehicle and to detect an inter-vehicle distance from the vehicle to the trapped preceding vehicle; a driving force controller to control a driving force transmitted from a prime mover to a road wheel axle; a brake controller to control a braking force applied to road wheels of the vehicle; and a vehicular velocity controller including a target inter-vehicle distance calculating section that calculates a target inter-vehicle distance on the basis of the vehicular velocity detected by the vehicular velocity detector and the inter-vehicle distance detected by the inter-vehicle distance detector, a first vehicular velocity controlling section that performs a vehicular velocity control such that the vehicle follows up the preceding vehicle maintaining the inter-vehicle distance at the target inter-vehicle distance through at least one of the driving force controller and the brake controller to bring the detected inter-vehicle distance substantially coincident with the target inter-vehicle distance, and a vehicular deceleration stopping section that performs a vehicular deceleration control in accordance with the inter-vehicle distance from the vehicle to the preceding vehicle immediately before a time point at which the inter-vehicle distance detector which trapped the presence of the preceding vehicle has not detected the preceding vehicle to stop the vehicle when the vehicular velocity detected by the vehicular velocity detector falls in a low vehicular velocity region lower than a predetermined velocity value and the inter-vehicle distance detector which trapped the presence of the preceding vehicle has not detected the preceding vehicle.
According to another aspect of the present invention, there is provided a preceding vehicle following control method for an automotive vehicle, comprising: detecting a vehicular velocity of the vehicle; trapping a presence of a preceding vehicle which is running ahead of the vehicle and to detect an inter-vehicle distance from the vehicle to the trapped preceding vehicle; controlling a driving force transmitted from a prime mover to a road wheel axle; controlling a braking force applied to road wheels of the vehicle; calculating a target inter-vehicle distance on the basis of the detected vehicular velocity and the detected inter-vehicle distance; performing a vehicular velocity control such that the vehicle follows up the preceding vehicle maintaining the inter-vehicle distance at the target inter-vehicle distance through controlling at least one of the driving force and the braking force to bring the detected inter-vehicle distance substantially coincident with the target inter-vehicle distance; and performing a vehicular deceleration control in accordance with the inter-vehicle distance from the vehicle to the preceding vehicle immediately before a time point at which the trapped preceding vehicle has not been detected when the detected vehicular velocity falls in a low vehicular velocity region lower than a predetermined velocity value and the trapped preceding vehicle has not been detected.
This summary of the invention does not necessarily describe all necessary features so that the invention may also be a sub-combination of these described features.